1 /*
   2  * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 #ifndef SHARE_VM_MEMORY_METASPACE_SHARED_HPP
  25 #define SHARE_VM_MEMORY_METASPACE_SHARED_HPP
  26 
  27 #include "memory/allocation.hpp"
  28 #include "memory/memRegion.hpp"
  29 #include "runtime/virtualspace.hpp"
  30 #include "utilities/exceptions.hpp"
  31 #include "utilities/macros.hpp"
  32 
  33 class FileMapInfo;
  34 
  35 // Class Data Sharing Support
  36 class MetaspaceShared : AllStatic {
  37 
  38   // CDS support
  39   static ReservedSpace* _shared_rs;
  40   static int _max_alignment;
  41   static bool _link_classes_made_progress;
  42   static bool _check_classes_made_progress;
  43   static bool _has_error_classes;
  44   static bool _archive_loading_failed;
  45  public:
  46   enum {
  47     vtbl_list_size = 17, // number of entries in the shared space vtable list.
  48     num_virtuals = 200   // maximum number of virtual functions
  49                          // If virtual functions are added to Metadata,
  50                          // this number needs to be increased.  Also,
  51                          // SharedMiscCodeSize will need to be increased.
  52   };
  53 
  54   enum {
  55     ro = 0,  // read-only shared space in the heap
  56     rw = 1,  // read-write shared space in the heap
  57     md = 2,  // miscellaneous data for initializing tables, etc.
  58     mc = 3,  // miscellaneous code - vtable replacement.
  59     n_regions = 4
  60   };
  61 
  62   // Accessor functions to save shared space created for metadata, which has
  63   // extra space allocated at the end for miscellaneous data and code.
  64   static void set_max_alignment(int alignment) {
  65     CDS_ONLY(_max_alignment = alignment);
  66   }
  67 
  68   static int max_alignment() {
  69     CDS_ONLY(return _max_alignment);
  70     NOT_CDS(return 0);
  71   }
  72 
  73   static void prepare_for_dumping() NOT_CDS_RETURN;
  74   static void preload_and_dump(TRAPS) NOT_CDS_RETURN;
  75   static int preload_and_dump(const char * class_list_path,
  76                               GrowableArray<Klass*>* class_promote_order,
  77                               TRAPS) NOT_CDS_RETURN;
  78 
  79   static ReservedSpace* shared_rs() {
  80     CDS_ONLY(return _shared_rs);
  81     NOT_CDS(return NULL);
  82   }
  83 
  84   static void set_shared_rs(ReservedSpace* rs) {
  85     CDS_ONLY(_shared_rs = rs;)
  86   }
  87 
  88   static void set_archive_loading_failed() {
  89     _archive_loading_failed = true;
  90   }
  91   static bool map_shared_spaces(FileMapInfo* mapinfo) NOT_CDS_RETURN_(false);
  92   static void initialize_shared_spaces() NOT_CDS_RETURN;
  93 
  94   // Return true if given address is in the mapped shared space.
  95   static bool is_in_shared_space(const void* p) NOT_CDS_RETURN_(false);
  96 
  97   static void generate_vtable_methods(void** vtbl_list,
  98                                       void** vtable,
  99                                       char** md_top, char* md_end,
 100                                       char** mc_top, char* mc_end);
 101   static void serialize(SerializeClosure* sc);
 102 
 103   // JVM/TI RedefineClasses() support:
 104   // Remap the shared readonly space to shared readwrite, private if
 105   // sharing is enabled. Simply returns true if sharing is not enabled
 106   // or if the remapping has already been done by a prior call.
 107   static bool remap_shared_readonly_as_readwrite() NOT_CDS_RETURN_(true);
 108 
 109   static void print_shared_spaces();
 110 
 111   static bool try_link_class(InstanceKlass* ik, TRAPS);
 112   static void link_one_shared_class(Klass* obj, TRAPS);
 113   static void check_one_shared_class(Klass* obj);
 114   static void link_and_cleanup_shared_classes(TRAPS);
 115 };
 116 #endif // SHARE_VM_MEMORY_METASPACE_SHARED_HPP